1. Technical Field
The present disclosure relates to devices and methods for the removal of internal tissue and, more particularly, to snare-type devices including a pair of electrodes for treating tissue prior to excision.
2. Background of Related Art
A polyp is an abnormal growth of tissue projecting from a mucous membrane. A polyp that is attached to the surface of the mucous membrane by a narrow elongated stalk is said to be pedunculated. If no stalk is present, the polyp is said to be sessile. Polyps are commonly found in the colon, stomach, nose, urinary bladder and uterus. Polyps may also form elsewhere in the body where mucous membranes exist, for example, the cervix and small intestine.
The surgical procedure for removing a polyp is generally referred to as a “polypectomy”. Polypectomys are generally endoscopic or laparoscopic procedures performed through the oral or anal cavities. When the location of the polyp permits, the polypectomy may be performed as an open procedure. Conventional polypectomys are completed using various apparatus and techniques known in the art.
As noted above, there are two forms of polyps, sessile and pedunculated. The stalkless or sessile polyps are generally removed using electrical forceps. For example, the excess tissue projecting from the mucous membrane is cauterized and torn from the tissue wall. Pedunculated polyps, or those with stalks, tend to be larger with a greater blood supply. The size and shape of pedunculated polyps typically do not lend themselves to being removed using traditional forceps. Unlike sessile polyps, polyps with a stalk cannot simply be grasped in the jaw members of an electrosurgical forceps and be torn from the tissue wall. Instead, the polypectomy is performed using a surgical snare device.
Conventional snare devices are configured with a snare for looping over the distal end of a hanging polyp and tightening securely around the stalk of the polyp. By constricting the snare, and selectively applying energy to the snare, the device may cauterize or seal the polyp at the stalk as the polyp is severed from the tissue wall. Conventional snare devices may be configured for monopolar or bipolar use. Excising a polyp using a conventional snare device typically involves cutting or otherwise separating the polyp from the tissue wall as the snare device is activated and constricted about the stalk of the polyp. In this manner, the polyp is cauterized as the snare passes through the tissue.